Diaphragm pump



W 1929 A. LAMELHN 1K,719,60

DIAPHRAGM PUMP Original F 1925 :2 Sheets-Sheet 1 July 2, 192%. A. LAMEHJN 1,719,060

DIAfHRAGM PUMP Original Filed Oct. 5, 1925 2 Sheets-Sheet 2 a 3 0 R Q r;

Patented July 2, 1929 UNITED STATES PATENT OFFICE."

Annxannnn taunting or rams, Eamon;

DIAPHRAGM PUMP.

Original application filed October 5, 1925, Serial No. 60,436, and in France December 5, 1924. Divided and this application filed July 20, 1926. Serial No. 123,620.

m A diaphragm pump according to the invention, is characterized in particular by an auxiliary diaphragm, arranged in the chamber which forms the pump body and in which the. main diaphragm moves, said auxiliary diaphragm constituting a wall which is rigid and permits the working of the diaphragm pump as long as the pressure in the pump body remains below a determined value, whilst said auxiliary diaphragm yields and follows the main diaphragm in its displacement as soon as the pressure becomes excessive in the pump body. In this manner any Variation of volume in said pump body is prevented and working of the pump arrested. The preferred form of the invention is shown in the accompanying drawings in which V Figure 1 is a plan view of the pump; Figure 2 is a partial section of said pump so through a vertical plane corresponding to the line 2-2' of Figure 1.

Figure 3 is a partial section of the pump corresponding to the line 33, of Figure 2. y The pump illustrated in Figures 1-3 is formed by the combination of two diaphragm pumps 1 and 2 joined together and symmetrically arranged with reference to the plane Each of said pumps consists of a pump body 3 and a casing 4 containing the working mechanism; these two elements being separated from each other by. three deformable diaphragms5 of vulcanized fibre and of considerable thickness, kept at a suitable distance apart from one another and separated by two diaphragms 5 forming soft and impermeable joints.

The edges of each deformablediaphragm 5 and of each softer diaphragm 5 are tight- 1 ly held between the edges of the pump body 32nd of the casing 4, andform an impermeable joint there.

The pump bod 3, upon the vertical axis e z, is provide with a petrol filter and valves. The filter consists of an inlet petrol tube 6 with lateral orifices '2'. Such tube is screwed in the pump body properly so called and to its upper extremity is applied 'a she t of filtering material 10, such as c-hai'mvis leather, metallic gauge, etc. the lower edge of which is tightened by a ring 11 on to the periphery ofthe tube.

The suction valve 12 and the delivery valve 13 acting simply by virtue of their weight are arranged above the petrol filter B5 in the pump body, whilst the suction. valve 12 is in proximity to the upper extremity of the petrol inlet tube 6.

The pump body communicates with the suction chamber15 through a pipe 16 which terminates between the valves 12 and 13.

A perforated socket '17, witha fastening cap 18 is screwed to the top of the pump body 3 and places said pumpbody in com-. munication through the pipe 19 wlth a pipe 20 which delivers the petrol to the carburettor. Y

The pump 20 is common to the two diaphragm pumps land 2. r

The casing 4 which contains theniechanism is common to the two pumps 1 and 2 and carries two plates 23 in each of which slides a piston 24. a

Devices for filling; such as screwed stoppers 100 100 are provided in said casing and make itpossible to constantly maintain the same filled with lubricant. Consequently the diaphragms 5; 5 of the two twinpumps keep between them a constant quantity of lubricant, which thus forms a liquid pad be- 91) tween the two diaphragms and prevents them from being torn.

Each piston 24 isfixed by a bolt 25 in the centre of the corresponding deformable; diaphragms '5, 5 Said piston 24 is provided with a plunger 40 which a spring 41 keeps, away from the body of the piston itself and constantly'pushes it into engagement with A the driving cam 27. I

The two pistons 24 are joined together by a web 26 within which is lodged the rotary cam 27 forming an integral part of the driving shaft 28.

The pump is also provided with a safety device to prevent any excessive pressure in the pump body. Thls device consists of an auxiliary diaphragm' 101 mounted in the pump body 2 and in contact by 1ts internal face with the'inner chamber of the pump i the rin provide with a lock nut 113.

.The pump above described normally works in the following'manner:--The cam 27, by rotating in the direction of the arrow 35, pushes the plunger 40 which, by

.means of the spring 41, pushes the. piston 24 of pump 1. Said piston isdisplaced in the direction of arrow 36 and carries with it the diaphragm 5 which determines a depression in the suction chamber 15. The valve 12 rises, the petrol issucked up into the pump body 3, enters the same through the inlet tube 6, passes through the orifices of said tube 7, traverses the chamois leather 10, where it is cleared of its impurities, passes through the lifted-valve 12 and fills up the chamber 15.

'When the cam, whilst continuing to rotate in the direction of the arrow 35, pushes back the piston 24 in the opposite direction tothe arrow 36 the deformable diaphragm 5 drlves the petrol in the chamber 15. he

petrol raises the delivery valve 13, passes through the orifices in the socket 17, follows the pipe 19 and flows through 20 into the carburettor.

' The two pumps 1 and 2 work in opposite directions to each other under the influence of the single cam 27 that is to say, that one of the pumps sucks up, when the other delivers or vice versa'.

The two diaphragms 5, 5 of the twin pumps 1 and 2 are made dependent upon each other by the cross-piece .or web 26 .in

' such manner that the effects of atmospheric thedisplacements of the and of the pressures of the distributed liq- ..u1d. A constant supply or a constant prespressure or any other pressure acting on the opposite faces of these dia hragms respectively in the direction 1, neutralize one b another. Consequently the displacements of said diaphragm are now only'a function of drivin parts 27 Sureor both these conditions at the same t me are obtained whatever may be the vari atlons' n the atmospheriepressure, and consequently whatever may be the altitudes reached by the aircraft, if the pump feeds the explosion motors of such aircraft.

The arrangement thus automaticallyensures a barometric or altimetric compensatron.

The auxiliary diaphragm 101 represents another safety device assuring similar advantages.

' Under normal working, the princi al dia phragm 5, 5 under the influence 0 piston 24 receives to and fro motions in the direction 36 and in the opposite direction. These motions determine in the usual way variations in the capacity of the chamber 15' and consequently a suction of petrol through the valve 12 and the delivery of said petrol through the valve 13 into the utilization pipe towards the carburettor.

On the contrary, ifthe pressure in the.

chamber 15 tends to become too high owing, 1

for instance, to the delivery "alve 13 being blocked, the spring 111 will become com- .pressed' and the auxiliary diaphragm 101 follows exactly the displacement of the principal dia hragm 5, 5 Consequentl the volume 0 liquid contained in the chem or 15 between the. two flexible dia hragms 5, 5', and 101 remains constant. N o further suction of petrol takes place through the valve 12 and the pressure in thechamber 15 can .no longer increase or cause the breaking of the principal diaphragm 5 5.

The tension of the spring 111 can also be regulated, as desired, by turning more or less the adjustable screw 112. The pressure in the chamber 15, under which the-sprin 111 becomes compressed, is thus regula and the auxiliary diaphragm 101 is allowedto follow the displacements of the principal diaphragm 5, 5

The nut 109 allows the course of the min iliary diaphragm 101 being so regulated that said. course should not be greater than that of the diaphragm 5, 5 in the" direction of the arrow 36.

, Numerous modifications may be introduced in the arrangement above described; the spring 111 in particular may be replaced y an other means to maintain the auxiliary iaphragm 101 stretched, in the case of normal ,pressure in the chamber and then yielding and allowing said diaphrefm to relax and follow the motions of the 1aphragm 5, 5' if said pressure tends to become too high.

Iclairnr a I A 1. In a feed pump, the following combination: a pump body; a suction valve and a delivery valve. mountedin said pum body; a main diaphragm mounted in sai ump body; a driving member controlling said diahragm; an auxiliary diaphragm mounted in pump body; and means exerting pres pressure on said auxiliary sure on theauxiliary diaphragm and maintaining it stretched as long as the "pressure in the pump body remains below a determined value, said means being arranged to yield as soon as this pressure acquires an excessive value, the auxiliary diaphragm then following the main diaphragm in its displacements WlllClt prevents any variation in volume ofthe pump body chamber and arrests the working of the pump.

2. In a. feed pump, the following combination: a pump body; a suction valve and a delivery valve mounted in nain diaphragm mounted in said pump body; a driving member controlling said diaphragm; an axuiliary diaphragm mounted in said pump body; and yieldable means exerting pressure on the auxiliary diaphragm and maintaining it stretched as lon as the pressure in the pump body remains elow a determined value, said means yielding as soon as the pressure acquires an excessive value, said auxiliary diaphragm then following the main diaphragm in its displacements which prevents any variation in volume in the pump body chamber and arrests the working of the pump.

3. In a feed pump, the following combination: a pump body; a suction valve and a delivery valve mounted in said pump body; a main diaphragm mounted in said pump body; a driving member controlling said diaphragm; an auxiliary diaphragm mounted in said pump body; means for exertin diaphragm and said pump body; a

maintaining it stretched as long as the pressure in the pump body remains below a determined value, said means yielding as soon as this ressure acquires an excessive value, the auxlliary diaphragm then following the main diaphragm in its displacements, which prevents any variation of volume in the pump body chamber and arrests the working -of the pump; and regulating elements for adjusting said auxiliary diaphragm pressure means.

4. In a feed pump, the following combination: a pump body; a suction valve and a delivery valve mounted in said pump body'; a main diaphragm mountedin said pump body; a driving member controlling said diaphragm; an auxiliary diaphragm mounted in said pump body; means for exerting pressure on said auxiliary diaphra m and maintaining it stretched as long as the pressure in the pump body chamber remains be low a determined value, said means yielding as soon as the pressure acquires an excessive value, the-auxiliary diaphragm then following said main diaphragm in its displacements w'hichprevents any variation of volume in the'pump body chamber and arrests the working of the pump; and abutment elements connected in an adjustable manner with said auxiliary diaphragm and permitting regulation of the extent of movement thereof.

In testimony whereof I afiix my signature.

ALEXANDRE LAMBLIN. 

